Nephtys cirrosa and Bathyporeia spp. in infralittoral sand

SS.SSa.IFiSa.NcirBat

SS.SSa.IFiSa.NcirBat recorded () and expected () distribution in Britain and Ireland (see below)

For a list of 2004 characterising species please see the JNCC website.

Species indicative of sensitivity

To assess the sensitivity of the biotope, the sensitivity of component species is reviewed. Those species that are considered to be particularly indicative of the sensitivity of the biotope, and for which research has been undertaken in detail are shown below (see selection criteria). The biology of other component species of the biotope is also taken into account wherever information is known to the researcher.

Explanation

The faunal composition of this biotope is determined by physical rather than biological forces and species present need to be resilient to disturbance of the substratum, hence mobile polychaetes and crustaceans constitute the dominant fauna. Withers & Thorp (1978) observed that the ability of small crustaceans and polychaetes to re-enter the sediment rapidly after having been washed out of the substratum is of great importance for their persistence in the system. Nephtys cirrosa is the dominant polychaete. Many authors mention a strong influence of the sediment type on the distribution of the genus Nephtys (e.g. Clark & Haderlie, 1960; Clark, Alder & McIntyre, 1962; Hammond, 1966; Wolff, 1973) and Nephtys cirrosa demonstrates a preference for high energy environments with clean coarse grained sand. Bathyporeia pelagica represents the mobile crustacean fauna.

Additional information

The occurrence of rare species and very high diversity is unusual in mobile sandbanks. However, important species of interstitial polychaete may be recorded within the biotope, for instance, Polygordius appendiculatus, which has a preference for coarse and medium sands. In mobile subtidal sandbanks in the North Sea, Vanosmael et al., (1982) found exceptional numbers of Epilonematidae and Draconematoidea (Nematoda) and three important species of interstitial polychaetes, Polygordius appendiculatus, Protodriloides chaetifer and a species of the genus Protodrilus. Such species are adapted to the extreme instability of the substratum of the sandbanks and are confined to such biotopes (Elliott et al., 1998).